Slide-valve for compound engines



(No Model.)

' E. G. DAVIS.

SLIDE VALVE FOR COMPOUND ENGINES. No. 274.571. Patented Mar. 27, 1883.

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PATENT EDWARD G. DAVIS, OF ST. LOUIS, MISSOURI.

SLIDE-VALVE FOR COMPOUND ENGINES.

SPECIFICATION forming part of Letters Patent No. 274,571, dated March 27, 1883.

Application filed January 22, 1883. (No model.)

To all whom it may concern:

Be it known that I, EDWARD G. Dnvrs, a citizen of the United States, residing at the city'of St. Louis, andState of Missouri, have invented certain new and useful Improvements in Slide-Valvefor Compound Steam-Engines; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawing, and to the letters and figures-of reference marked thereon, which form a part of this specification.

This invention relates to compound steamengines where the steam expands in two stages in separate cylinders; and it consists in an improved slide-valve arranged to feed live steam to the first cylinder, to lead the partlye'xpanded steam to the second cylinder, and to lead the fully-expanded steam from that to the exhaust. This is made substantially as set forth hereinafter, and as shown in the drawing, which shows a vertical section.

The two cylinders A B are of unequal cross-section, but of like lengths. They are arranged end to end in one line, and haveone piston-rod,0,extendingcentrally through both, with piston-heads EF, as shown. The steamchest D extends partly over each cylinder, and contains the valve V, arranged to move from r the position shown to that indicated by dotted passes from port Q, by passage G and port P,

to chamber R in cylinder B, to push the piston-head Fin the same direction with force equal to the difference in cross-section of the two cylinders, and at the same time the expanded steam in chamber S will pass, by passage and port T, passage K, and port U, to

the exhaust. At the end of the stroke the valve V is shifted to the position shown in dotted lines, so as to change the registry of the passages with the ports. Then the live steam will pass, by channel I, from the steamchest D and port Q to chamber 0 of cylinder A, to push the piston-head E to the other end again by expansion. The partly-expanded steam will pass from chamber M, by port N, passage H, and port T, to the outer end of cylinder B to chamlier S, so as to push pistonhead F back again, while the expanded steam will pass from chamber R, by port P and-pas sage K, to port U, to escape to the exhaust, when the valve returns to first position. The same arrangement can he made if two separate pistons are used instead of one. The several ports are all on one level, so the fitting is sim-- ple. The several passages in the valve Vare each separateand simple. The passage of the steam in each case is as short and direct as possible, and there are no idle ports to the passages in use to leak steam.

Various modifications can be made in the valve and the arrangements.

The two cylinders are set apart with bridgeconnections to hold them together, and with interspace J to permit the use and adjustment of separate packing on the piston-rod for each, as shown.

I reserve the privilege of using any of the subject-matter shown in this case in one or more future applications, and to claim therein anything which might be, but which may not be, fully patented in this case.

I claim v 1. In a compound engine, a slide-valve having independent passages H Gr, arranged to transfer partly-expanded steam from one cylinder to the other, passage K,'to transfer expanded steam from cylinder R to the exhaust, and channel I, to admit live steam to chamber 0, substantially as and for the purposes set forth;

ALPHONSE F. PERRIER, SAML. S. VAIL.

2. In a compound engine having two cyl- 

